General Design Guidelines & Schedule of Design Elements For
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General Design Guidelines & Schedule of Design Elements For the Haw River Trail Conceptual Greenway Master Plan From the Indian Valley Golf Course to Glencoe Mill Village August 2007 Prepared for The City of Burlington Recreation and Parks Departments In partnership with The Alamance County Recreation and Parks Department Funded by the North Carolina Trails Program Prepared by the Piedmont Triad Council of Governments ______________________________________________________________________________ General Haw River Trail Design Guidelines The following general trail design guidelines illustrate typical trail dimensions and construction practices for the Haw River Trail (HRT) system. They are intended to be used as suggested practices for constructing the HRT system and may not apply to every situation, based on varying site conditions. Trail Construction Guidelines Trail construction standards for the HRT are defined for both urban and rural trail cross-sections designed for use by pedestrians, hikers, bicyclists and horseback riders in some sections. The urban cross-section (see Figure 1 below) can be constructed in the more densely populated urban regions of the trail, with the rural cross-section (see Figure 2 below) applied in the more rural &/or environmentally sensitive areas. The HRT is a non-motorized trail. See Table 1 below for trail construction guidelines for both the urban and rural cross-sections. Figure 1 – Urban Cross-Section Trail Construction Guidelines Recreational Trail Design and Construction – University of Minnesota Extension Service, 2007 ______________________________________________________________________________ Haw River Trail Conceptual Greenway Master Plan Page 1 ______________________________________________________________________________ Figure 2 – Rural Cross-Section Trail Construction Guidelines Recreational Trail Design and Construction – University of Minnesota Extension Service, 2007 ______________________________________________________________________________ Haw River Trail Conceptual Greenway Master Plan Page 2 ______________________________________________________________________________ Table 1 – Trail Construction Guidelines for Urban & Rural Cross-Sections DESIGN ELEMENT URBAN TRAIL CROSS SECTION RURAL TRAIL CROSS SECTION Clearing Width 10 to 14 feet 7 to 9 feet Tread Width 6 to 10 feet 3 to 5 feet Tread Surface 4 inches crushed rock base Natural / native soil that has been compacted Firebreak (optional) 10 feet of fire resistant native N/A vegetation on each side of trail. Total corridor width should equal 30 feet DESIGN ELEMENT URBAN AND RURAL CROSS SECTIONS Percent Grade Grades should not exceed 10 percent because they become difficult for trail users to sustain & lead to trail erosion problems. Desired Grade: 0 to 5 percent Maximum Grade: 5-10 percent (sustained), 15 percent (shorter than 50 yards) Out-Slope Grade: 4 percent (maximum) Clearing Height 8 – 10 feet (10 - 12 feet to allow for horseback riding). Additional clearance may be needed to compensate for branches drooping with heavy rain or snow. Trail Layout Wet areas and steep slopes pose extreme difficulties to trail maintenance and should be avoided. Keep water and motorized road crossings to a minimum. Frequently occurring curves and grade changes will add interest. Turning Radius Wide, gentle curves with good forward sight distances are critical for safety, aesthetically pleasing, and easier to maintain. Avoid sharp-angled turns, turns on steep slopes, or turns at the base of a hill. Sight Distances Forward sight distances of 100 feet (50 feet minimum) are important because the trail may be shared by hikers, equestrians, and bicyclists. Although curves should be carefully designed to maintain good sight distances, turns and bends tend to help reduce travel speeds and add variety to the trail experience. Road Crossings Motorized road crossings must be carefully located, designed, and signed 100 to 200 feet in advance to insure that trail users and vehicle drivers have good sight distances in all directions. ______________________________________________________________________________ Haw River Trail Conceptual Greenway Master Plan Page 3 ______________________________________________________________________________ Table 1 – Trail Construction Guidelines for Urban & Rural Cross (continued) DESIGN ELEMENT URBAN AND RURAL CROSS SECTIONS Some water crossings along the HRT require bridges. Bridges should generally be used in areas of perennial and Water Crossings intermittent stream crossings. However, slow-moving water less than 24 inches deep may be forded or culverted. Bridge design should meet the following requirements: • meet the needs and weight of horse travel; • orient planking at a 45- to 90-degree angle to the direction of travel, gaps between planking oriented in the direction of travel may trap bicycle tires and endanger trail users; • make approaches straight, level, and when possible, at least 100 feet long; • must be located above ordinary high water mark; • have railings or log barriers on both sides; • have an 8-foot minimum width for horses; and • weight capacity varies depending on maintenance equipment and length of bridge. Parking area with space for trailers, picnic area, resting areas, Other Facilities overlooks, campsites, water, information board, signs, hitching post or tether line, horse corral, sanitation facilities, restrooms. • Helps with orientation and way-finding Signage • Helps with safety issues such as road crossings • Shows etiquette for all users • Gives distances Recreational Trail Design and Construction – University of Minnesota Extension Service, 2007 Trail Accessibility Guidelines An important part of trail design is designing for accessibility that will allow everyone to enjoy a trail experience. Communities planning and constructing portions of the HRT have an opportunity to develop segments of the trail that are accessible. Accessible segments could be located anywhere along the trail, but locating them in more urban areas that are using the urban trail cross- section standards would best serve most users. Much of the following guidance on how to make the HRT accessible comes from the Americans with Disabilities Act Accessibility Guidelines (1991) and Designing Sidewalks and Trails for Access (1999). For more specific information about accessibility, reference these materials. ______________________________________________________________________________ Haw River Trail Conceptual Greenway Master Plan Page 4 ______________________________________________________________________________ Accessible trails should be free of debris and avoid motorized roadway crossings whenever possible. Crushed rock or a road base material with a high clay content that has been rolled and compacted may be used for wheelchair access. Trail grades should be generally flat (5 percent maximum grades for short distances) and regular rest stops provided. The cross-slope should not be greater than 2 to 6 percent. Bridges should have handrails, and their decks must be flush with the trail surface. Decking boards on bridges and boardwalks should be positioned perpendicular to the trail path with gaps between boards not exceeding .375 inches. Visually impaired persons can use natural trail treads with guide ropes or definite edges such as logs or railroad ties. An accessible trail information sign should be place at the trail entrance that describes the length and difficulty of the trail, the location of rest stops, and any potential trail hazards. Rest rooms, parking lots, and ramps should be carefully designed to ensure access. Guidelines for Sustainable & Aesthetic Trail Construction A sustainable trail surface can be created with minimal disturbance and maximum variety and interest as the following goals are met: • Minimize soil disturbance in order to allow plants and animals the best chance for survival; aesthetic appeal will be correspondingly high. • Eliminate the potential for erosion. • Use correct and aesthetic pruning or removal of tree limbs and shrubs. • Minimize drainage problems by removing water from the trail at the first opportunity. • Do not allow water to stand on the trail. • Maintain existing drainage patterns whenever possible; do not force nature. • Outslope the trail to dispose of sheet drainage and carefully shape the trail back-slope to prevent erosion. • Coordinate excavation with vegetation and drainage considerations. • Use select borrow or retaining walls to improve in adequate trail surfaces. • Attain proper slope and compaction through a detailed analysis of on-site conditions during wet and dry periods. • Make decisions to benefit the trail users. • Remove sharp plants from close proximity to the trail. • Consider the physical and visual relationship of vegetation to the trail. • Where appropriate, narrow the clearing width by leaving brush close to the trails edge; excessive clearing allows bicycles to travel faster and leave the trail when cornering. • Retain dead standing trees (i.e. “snags”) when safety permits to provide homes and feeding locations for wildlife. • Consider erecting nest boxes or creating artificial snags in woodlands near the trail route. ______________________________________________________________________________ Haw River Trail Conceptual Greenway Master Plan Page 5 ______________________________________________________________________________ Rural Trail Cross-Section Construction Guidelines Step One - Stake the Route • Stake the trail